Squeegee operating and control mechanism



April 3, 1951 s. L. FRANK SQUEEGEE OPERATING AND CONTROL MECHANISM FiledSept. 25, 1948 2 Sheets-Sheet 1 llllllllllllllllIHHHIIHIIHIHIIIIIF H HTIIHIIIIHIIHIIHIIHHIIIIllllllllllll ll INVENTOR.

STANLEY L. FRANK BY 13mg, fi tbv H/S ATTORNEYS Patented Apr. 3, 1951UNITED STATES PATENT OFFICE SQUEEG-EE OPERATING AND CONTROL MECHANISMStanley L. Frank, Oakland, Calif. Application September 25, 1948,'Serial No. 51,283

10 Claims. 1

My invention relates to screen printing appara- 'tus and moreparticularly to squeegee operating and control "mechanism for suchapparatus.

Among the objects of my invention are:

1) To -provide a novel and improved squeegee operating and controlmechanism for screen printing apparatus;

(2) To provide a novel and improved squeegee operating and controlmechanism for screen printing apparatus, .in which the squeegee shallautomatically reverse at the termination of each stroke;

. (3) To provide a novel and improved squeegee operating and controlmechanism for screen printing apparatus which will assure substantiallyuniform continuous pressure of the squeegee against the screenthroughout the effective stroke of the squeegee;

(4 To provideia novel and improved squeegee operating and controlmechanism for screen operating and control mechanism for screen printingapparatus, in which the squeegee terminates its stroke in a reversal ofposition, ready .for the start of its return stroke.

Additional objects of my invention will be brought out in the followingdescription of a preferred embodiment of the same, taken .in conjunctionwith the accompanying drawings Whereiri- I Figural :is an .elevational.view in .section, taken longitudinally through the screen printingapparatus with my novel and improved squeegee operating and controlmechanism installed;

Figure 2 is a fragmentary plan view of the .apparatus of'Figure 1;

Figure 3 .is an elevational View in section, transverselynf theapparatus of Figure 1 and taken in the plane 3-3 of Figure 1;

Figure 4is a three-dimensional view-of .oneend of the squeegee operatingand control mechanism of the present invention;

Figure 5 is a view .in section through the squee and control mechanismof Figure ne end thereof in elevation.

Referring ,to the drawings for details of the preferred. embodiment ofthe present invention, the same is shown installed in conventionalscreen printing apparatus involving a platen 1 supported one frame 3 towhich is .hingedly secured arectangular frame 5 "on. which is stretcheda silk screen -'I enaloling the screento be raised and lowered withrespect to the surface 01' the platen. 4

Ink or paint 9 "employed in printing is placed on the upper surface ofthe screen and spread over the surface thereof by means of a squeegee Hwhich is run over the surface of the screen in the process of printing.

A sheet l'3 of blank paper, placed 'upon "the platen beneath the silkscreen, will receive such paint as penetrates through the pores of thescreen during such movement of the squeegee. By placing a stencil 15intermediate the screen and such paper, the stenciled information willbe reproduced on the paper. The paint in the meantime causes the stencilto efiective'ly adhere to the undersurface of the screen, whereby, uponlifting the screen following a stroke of the squee- 'gee,the paper withits printed information thereon may be freely removed from the platenand a fresh sheet of paper substituted.

The present invention resides specifically in the mechanism foroperating and controlling the squeegee, which, in the present invention,is adapted to function on both its forward and return strokes, and isdesigned to push the ink or paint ahead of it, as I have found this toproduce .more uniform results, in that the tendency for a squeegee toride over the ink supply is thereby minimized.

.Such operatingand control mechanism involves mean'smounted on andextending along eachlongitudinal side of the screen frame for movablysupporting .a squeegee carrier assembly. Such supporting means includesa track 11 and associated rack [9 running along the longitudinal side ofthe screen .frame, and a guide rail 2| running along the inner side ofthe upper edge of .a side wall 2.3, to fixedly support such guide rail.in parallel relationship .to the track and associated-rack.

The squeegee carrier assembly involves a pair of carriers 25, one forveach end of the squeegee .H which is adapted to span the width of theprintin screen. Each such end carrier includes a pair of assemblies,one, 2!, which slidably engages the track for-slidable movementtherealong, while the other assembly 129 is resistively supported by thetrack-engaging assembly and slid- :ably engages the guide rail .2]

With respect to details of construction, the track-engaging (assemblyinvolves a block 3| having a longitudinal groove .in its undersurfacepermitting the block to straddle the rack and rest upon the track; Thecorresponding blocks of each carrier are interconnected by an angle ironve sal of position of the squeegee.

cross-piece 35 spanning the screen frame. Pivotally secured to thecorner of each of the aforementioned blocks, on the inner surfacethereof serton in a perforation provided in a squeegeev mount for thepurpose. Upon raising the squeegee mounts about their pivot axes, itwill be apparent that the squeegee will be lifted from its operativeposition on the screen.

The resistively supported assembly 29 comprising the upper portion of acarrier, comprises a strip 45 having end brackets 41 and 49 adapted toslidably engage the guide rail and thus support the strip for slidablemovement adiacent the inner edge of the guide rail. This strip is formedwith a longitudinal slot 5! exten ing practically the full lengththereof to receive a bolt or machine screw 53 extending downwardlythrough the slot and threadedly engag ng the bearing block below, suchbolt limiting the permissible movement of the strip with respect to thebearing block. l v

The slotted strip carries alon its upper surface adjacent its inneredge. a lift-and-reversing cam 55. This cam is in the form of a flatsegment standing on edge, the cam surface being formed by the upper edgeof the segment sloping upwardly toward a peak from each end.

Such cam surface is adapted to be en aged by a cam follower or roller 51which in the operating position of the squeegee, will occupy a positionat one end of the cam.

As thus far described, if the upper or cam assembly 29 were held againstmovement a ong the guide rail, and pressure were brought to bear againstthe bearing block to produce relative movement between the trackengaging assembly and the cam assembly, the squee ee mount at each endof the squeegee will be l fted about its pivot axis as the cam followeron the squeegee mount is forced to ride up the adjacent cam surfacetoward the peak of the cam: and as the squeegee mounts are thus lifted,the squeegee itself will be tilted upward to a vertical plane and raisedabove the screen .to the position depicted in Figure 5.

Cont nued relative movement between the two assemblies will cause the,cam follower to descend on the other s o e of the cam to gradually dropthe squeegee back into contact with the screen and reverse its pos tion.

Such revers ng action of the squeegee is only desired however, at thetermination of each stroke, and accordingly to secure such acton at thepro er time, I provide a stop pin 59 on, the guide rail at a pointapproaching the end of each stroke, so that as the cam assemblv strikesor abuts such a stop pin, to halt further movement th eof in the dirction in whi h it as tra el n 'sufficient additional movem nt of thebear ng block will be ermitted to effect the desired re- It is notedthat the cam is not s mmetrical in the embodiment of the inventionillustrated. and

this is attributable tothe fact that in the reversed pos tion of thesqueegee, it will not necessarily pensate for this condition.

The reciprocating movement of the squeegee is imparted thereto by a rodBl hingedly secured to the angle iron cross member 35 at the mid-pointthereof, such rod constituting either a piston rod or a lever in a powerapplication system.

The squeegee of the present invention is so mounted as to push the inkor paint ahead of it, as distinguished from the conventional method ofdragging the ink along with it. A more positive and effective spreadingof the coloring material over the screen is thereby assured.

Means are provided for equalizing the movement of the aforementioned endcarriers 25 with respect to each other, to assure that one end of thesqueegee shall not travel ahead of the other during any portion of itsstroke, or, in other words, to maintain the squeegee at all times normalto its direction of movement.

Such means includes an equalizer shaft 63 journalled at each end in oneof the bearing blocks. Each such bearing block is formed to provide achamber for housing a pinion 65 mounted on such equalizer shaft adjacentthe associated journalled end and in engagement with the rack. With suchequalizer means installed and functioning, one end carrier assemblycannot move ahead of the other during any portion of the stroke of thesqueegee, and consequently the squeegee itself will necessaril remainnormal to its direction of movement at all times.

During the operating or functioning portion of the squeegee stroke, thesqueegee is maintained in proper pressure contact with the screen byproviding at each end of the squeegee, suitable means for positivelyholding the squeegee in the desired pressure contact with the surface ofsuch screen.

Such means includes a pressure rail 61 affixed against the inner edge ofthe track, and extending substantially, though not quite, the wholedistance between stop pins. Affixed to each end of the squeegee bar forcooperation with such rail, is a pressure roller 68 adapted to engagethis rail and slide under it at the start of each stroke, the rail beingcammed at each end to facilitate such engagement. In this manner, thesqueegee will be positively held in its down or operating position at adesired pressure, until such roller rides from under such rail at theother end thereof, which is time to occur just prior to contact of theupper or cam assembly with a stop pin.

As the squeegee is thus depressed into pressure engagement with thescreen, the angular rotation of the squeegee about its mounting pins isin a direction tending to reverse the squeegee. To avoid probablereversals of the squeegee under such circumstances, I have found itdesirable that the squeegee be temporarily locked in the position itassumes at the end of each stroke so as not to be disturbed when thepressure rollers subsequently engage the pressure rails on thesucceeding stroke.

With this in mind, the mounting bracket 41 of the cam assembly is formedwith a notch 69 facing the associated squeegee mount 31, which mount isformed with an overhang H adapted to enter the notch at the terminationof the return stroke, whereby the mount becomes locked against movementon its pivot axis. During what may arbitrarily be considered the forwardstroke, it is contemplated that such locking engagement will over the'c'am in the DI'DOESSOfIeVBI'SiIIgTthG squee- -it being noted that bythis time the squeegee jpressure roller will have moved :out orengagement with the ?pressure 'rail and so will not inter- :dere withsuch :reversal of thesqueegee.

Following reversal of the squeegee at the .far end of the forwardstroke, :a similarulockin of the squeegee :occurs in preparation for thereturn :stroke. .At this point it is accomplished by pro- ;viding ashoulder 13 :on the squeegee mount, which is adapted to slide linfunderthe bracket-49 no "thereby :lock the mount against movement labout itspivot axis. V

:Fhom the above description of myrinvention in its preferred :form, itwill be apparent that the same rfulifills .all the objects recitedtherefor and while I have :diSjClOSEd my invention in its pre- {Ierred:form and in considerable detail, the same is subject to alteration andmodification without departing from the underlying principles thereof.1, accordingly, do not desire to be limited in my protection to suchdetails, except as may be necessitated by the appended claims.

.I claim:

1. Squeegee operating and control .mechanism ior screen printingapparatus of the type involving a platen and a removable screen thereon,comprising track means mounted on said table and extending along eachlongitudinal side of :such screen for movably supporting a squeegeecarrier assembly; a squeegee carrier assembly zmovably supportedthereon, said carrier assem ablytinvolving a carrier for each end-ofsuch squee- ;gee and a cross-bar interconnectin the same; each of saidend carriers including an assembly :sildably engaging said track means,and lift-andireversing cam means mounted on said track means engagingassembly; each of said track means engaging assemblies havinga camfollower Weir "lower associated therewith, :to eengage .and aside ill)engageable with said lift-and-reversing cam 7 :means; meansforreciprocally moving said squeeegee carrier assembly on said track means;[and means for .causing relative movement between said .cam means andsaid track means engaging assemblies as the end carriers approach thetermination of reach stroke.

'2. Squeegee operating and control mechanism for screen printingapparatus of the type involving a platen and a removable screen thereon,comprising track means extending along each longitudinal side of suchscreen for movably supporting ia squeegee carrier assembly; a squeegeeicarrier assembly movably supported thereon, said carrier assemblyinvolving-a carrier for each end of such squeegeeand a cross-barinterconnecting thesame; each of said end carriers including an assemblyslidably engaging said track means and lift-and-reversing cam meansresistively associ- :ated with said track means engaging assembly; 1a.squeegee end-supporting bracket secured :in each of said track meansengaging assemblies and having a cam follower engageable :with said'lift and-reversing cam means; means for reciprocally moving saidsqueege'ecarrier assembly on :said track means; means for causingrelative movement betweensaid cam means and said track ameans'engagingassembliesas the .end' carriers approach the termination of each stroke;and

:means for holdin a squeegee in desired pressure engagement with suchscreen during those portions of its strokes intermediate .suc'h period.of relative movement between said cam means and ,said track meansengaging assemblies.

.3; Squeegee operating and control mechanism or screen printingapparatus of the type involving :a "platen and ca removable screenthereon, comprising :track means mounted on said platen "and extending:along each longitudinal side .of such screen for imovably supporting a.squeegee carrier assembly; :a squeegee carrier assemblymovablysupported thereon, a carrier for each end of suchsqueegee and across-bar interconnecting the same; each of said "end carriers includingan assembly .slidably engaging said track means-and lift-and-reversingcam means resistively mounted on said track means engaging assembly; asqueegee end-supporting bracket secured in each of said track meanengaging assemblies and having a cam follower engageable with saidlift-andreversing cam means; .means for reciprocalh "moving saidsqueegee carrier assembly on said track means; and means 'for causingrelative vtmovement between said cammeans and said track means engagingassemblies as the end carriers 'approach'the termination of each stroke.Y

4. Squeegee operating and control mechanism "for screen printingapparatus of the type involvin a platen and a removable screen thereon,

comprising track means extending along each longitudinal side of suchscreen for movably supporting a squeegee carrier assembly; a squeegeecarrier assembly movably supported thereon and including a carrier foreach end of such squeegee,

each of said end carriers including an assembly slida'bly'en'gagingrsaid track means, and lift-andment of both said end carrierswith respect to each other; and means for causing relative movementbetween said cam means and said track means engaging assemblies as theend carriers approach the termination of each stroke.

5. Squeegee operating and control mechanism for screen printingapparatus of the type involving a platen and a removable screen thereon,comprising track means extending along each longitudinal side of suchscreen for movably supporting a squeegee carrier assembly; a squeegeecarrier assembly movab y supported thereon said carrier assemblyinvolving a carrier for each end of such squeegee and a cross-barinterconnecting the same; each of said end carriers including anassembly slidably engaging said track means, and lift-and-reversing cammeans resistively mounted on said track means engaging assembly; asqueegee end-supportin bracket secured in each of said track meansengaging assemblies and having a cam follower engageable with saidlift-andreversin cam means; means for reciprocally moving said squeegeecarrier assembly on said track means; means for equalizing the movementof both said end carriers with respect to each other; and "means forcausing relative movement between said cam means and said track meansengaging assemblies as the end carriers approach 'thetermination of eachstroke.

SJSqueegee operating and control mechanism for screen printing apparatusof the type involving a platen-and a removable screen thereon,

comprising means extending along each longi- 'tudinal side of saidscreen for movably supporting a sq eegee carrier assembly. said meansincluding a track along each of said longitudinal sides, a squeegeecarrier assembly 'movably mounted on said tracks, said carrier assemblyinvolving a carrier for each end of such squeegee; each such end carrierincluding a pair of assemblies, one slidably engaging such track and theother resistively supported by said track engaging assembly, alift-and-reversing cam in said resistively supported assembly, asqueegee end-supporting bracket pivotally secured in each of said trackengaging assemblies and having a cam follower engageable with saidlift-andreversing cam, and a cross-bar interconnecting said trackengaging assemblies; means for reciprocally moving said squeegee carrierassembly on said tracks; and means disposed in advance of thetermination of each stroke of said squeege carrier assembly forrestraining further movement of said resistively supported assemblies assaid assemblies approach the termination of each stroke, wherebycontinued movement of said track engaging assemblies to the end of eachstroke will cause said lift-and-reversing cams to lift and reverse asqueegee affixed to said squeegee end-supporting brackets.

'7. Squeegee operating and control mechanism for screen printingapparatus of the type involving a platen and a removable screen thereon,comprising means extending along each longitudinal side of said screenfor movably supporting a squeegee carrier assembly, said means includinga track along each of said longitudinal sides and a guide rail fixedlysupported in parallel relationship to said track, a squeegee carrierassembly movably mounted on said tracks, said carrier assembly involvinga carrier for each end of such squeegee; each such end carrier includinga pair of assemblies, one slidably engaging such track and the otherresistively supported by said track engaging assembly and slidablyengaging said guid rail, a life-and-reversing cam in said resistivelysupported assembly, a squeegee endsupporting bracket pivotally securedin each of said track engaging assemblies and having a cam followerengageable with said lift-and-reversin cam, and a cross-barinter-connecting said track engaging assemblies; means for reciprocallymoving said squeegee carrier assembly on said tracks; means forequalizing the movement of said end carriers with respect to each other;and means disposed in advance of the termination of each stroke of saidsqueegee carrier assembly for restraining further movement of saidresistively supported assemblies as said assemblies approach thetermination of each stroke, whereby continued movement of said trackengaging assemblies to the end of each stroke will cause saidlift-and-reversing cams to lift and reverse a squeegee affixed to saidsqueegee end-supporting brackets. I

8. Squeegee operating and control mechanism for screen printingapparatus of the type .in-

volving a platen and a removable screen thereon, comprising meansextending along each longitudinal side of said screen for movablysupporting a squeegee carrier assembly, said means including a track anda rack along each of said longitudinal sides and a guide rail fixedlysupported in parallel relationship to said track, a squeegee carrierassembly movably mounted on said tracks, said carrier assembly involvinga carrier for each end of such squeegee; each such end carrier includinga pair of assemblies, one slidably engaging such track and the otherresistively supported by said track engaging assembly and slidablyengaging said guide rail, a 'lift-and-reversing cam in said resistivelysupp'orte'd' assembly, a squeegee end-supporting bracket pivotallysecured in each of said track engaging assemblies and having a camfollower engageable with said lift-and-reversing cam; means forreciprocally moving said squeegee carrier assembly on said tracks; meansfor equalizing the movement of said end carriers with respect to eachother, said means including an equalizer shaft terminating at its endsin said track en'- gaging assemblies, and pinions carried by said shaftin meshing engagement with said racks; and means disposed in advance ofthe termination of each stroke of said squeegee carrier assembly forrestraining further movement of said resistively supported assemblies assaid assemblie approach the termination of each stroke, wherebycontinued movement of said track engaging assemblies to the end of eachstroke will cause said lift-and-reversing cams to lift and reverse asqueegee ainxed to said squeegee endsupporting brackets.

9. Squeegee operating and control mechanism for screen printingapparatus of the type involving a platen and a removable screen thereon,comprising means extending along each longitudinal side of said screenfor movably supporting a squeegee carrier assembly, said means includinga track and a rack along each of said longitudinal sides, a squeegeecarrier assembly movably mounted on said tracks, said carrier assemblyinvolving a carrier for each end of such squeegee; each such end carrierincluding a pair of assemblies, one'slidably engaging such track and theother resistively supported by said track engaging assembly, alift-and-reversing cam in said resistively supported assembly, asqueegee end-supporting bracket pivotally secured in each of said trackengaging assemblies and having a cam follower engageable with saidlift-and-reversing cam, and a cross-bar interconnecting said trackengaging assemblies; means for reciprocally moving said squeegee carrierassembly on said'tracks, said means including an actuating rod securedat one end to said cross-bar; means for equalizing the movement of saidend carriers with respect to each other, said means including anequalizer shaft terminating at its ends in said track engagingassemblies, and pinions carried by said shaft in meshing engagement withsaid racks; and means disposed in advance of the termination of eachstroke of said squeegee carrier assembly for restraining furthermovement of said resistively supported assemblies as said assembliesapproach the termination of each stroke, whereby continued movement ofsaid track engaging assemblies to the end of each stroke will cause saidlift-and-reversing cams to lift and reverse a squeegee aifixed to saidsqueegee end-supporting brackets.

l0. Squeegee operating and control mechanism for screen printingapparatus of the type involving a platen and a removable screen thereon,comprising means extending along each longitudinal side of said screenfor movably supporting a squeegee carrier assembly, said means includinga track and a rack along each of said longitudinal sides and a guiderail fixedly supported in parallel relationship to said track; asqueegee carrier assembly movably mounted on said tracks, said carrierassembly involving a carrier for each end of such squeegee; each suchend carrier including a pair of assemblies, one slidably engaging suchtrack and the other resistively supported by said track engagingassembly and slidably engaging said guide'rail. a

lift-and-reversing cam in said resistively supported assembly, asqueegee end-supportingbracket pivotally secured in each of said trackengaging assemblies and having a cam follower en- 10 whereby continuedmovement of said track engaging assemblies to the end of each strokewill cause said lift-and-reversing cams to lift and reverse a squeegeeafiixed to said squeegee endgageable with said lift-and-reversing cam,and 5 supporting brackets.

a cross-bar interconnecting said track engaging assemblies; means forreciprocally moving said squeegee carrier assembly on said track's, saidmeans including an actuating rod secured at STANLEY L. FRANK.

REFERENCES CITED The following references are of record in the one endto said cross-bar; means for equalizi g l0 file of thi patent:

the movement of said end carriers with respect to each other, said meansincluding an equalizer shaft terminating at its ends in said trackengaging assemblies, and pinions carried by said shaft in meshingengagement with said racks; 15

and means disposed in advance of the termination of each stroke of saidsqueegee carrier assembly for restraining further movement of saidresistively supported assemblies as said assemblies approach thetermination on each stroke, 20

UNITED STATES PATENTS Number Name Date 913,274 Erler Feb. 23, 19091,589,546 Nichols June 22, 1926 2,207,818 Perry et a1. July 16, 1940FOREIGN PATENTS Number Country Date 345,961 Germany Dec. 21, 1921

